东南大学编译原理试卷

9. Please construct the DAG for the following basic block. We assume that only variable P be used later, please optimize the block and rewrite the block in optimized code form.(10%)
1. Please construct context-free grammars with -free productions
for the following language (10%).
{| (a,b,c,d)* and the numbers of a’s and b’s and c’s occurred in
if (a[i,j] != a[j,i])
{
loop=1;
m=i;
n=j;
}
else j=j+1;
if (loop==0) i=i+1;
}
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Notes: Here we assume that the declaration of array A is array [1..10,1..10], each data element of array A would use 4 storage unit, and the start address of array A’s storage area is addrA.
Surname
Please obey the rules of examination. If you violate the rules, your answer sheets will be invalid
Southeast University Examination Paper (A)
Course Name Principles of Compiling Examination Term 0 8 - 0 9 - 2 Score
are even, and starts with b or c, ends with a}
2. Please construct a DFA with minimum states for the following regular expression. (10%) (a|(a|(a|b*))*)*(a|b*)
Student No.
3. Please eliminate the left recursions (if there are) and extract maximum common left factors (if there are) from the following context free grammar, and then decide the resulted grammar is whether a LL(1) grammar by constructing the related LL(1) parsing table.(15%)
Returned Address
Caller’s SP (Start Address of caller’s activation record)
SP
The C program is as the following: #include <stdio.h> int x,y;
int main() {
x=6; y=f(x); }
Productions
Semantic Rules
SL(1).L(2)
S.val=L(1).val+L(2).val/4L(2).len
SL
S.val=L.val
LL(1)B
L.val=L(1).val*4+B.val, L.len=L(1).len+1
LB
L.val=B.val, L.len=1
B0
E=A+B F=E-C G=F*D H=A+B I=H-C L=I+G M=I*I M=2*M N=L+M
P=N+M
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TOP Unit for Returned Value of function
Internal Temporary Work Units
Local Variable Data Storage Units
Formal parameter Storage Units
Number of Formal Parameters
are as following. Please construct the run-time stack map when it
gets the maximum size at the third time for the following C program(10%).共6页
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Storage Organization of C Language
Related Major
Software Engineering
Examination Form Close test Test Duration 150 Mins
There are 9 problems in this paper. You can write the answers in
English or Chinese on the attached paper sheets.
int f(int n) {
if (n<=1) return 1;
else if(n==2) return 2;
else { int t1,t2,t3,t; t1=f(n-1); t2=f(n-2);
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t3=f(n-3); t=t1+t2; t=t+t3; return t }
}
Notes: 1) Here we assume that the caller’s sp of Main function is the start address of global variable data area, and the returned address in the activation record of a function (including Main function) is filled by the operating system automatically, you might not care it.
….. Activation Record of the function called by Main function Activation Record of Main function Global Variable Data Area
The Form of Activation Record of any a function in C
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.(15%) EEE|EE|E*|(E)|a|b
6. Please construct an annotated parse tree for the input string
123.123 where the syntax-directed definition is as following (10%):
5. Please construct a LR(1) parsing table for the following ambiguous grammar with the additional conditions that *, and have the properties of left associative law, and * has higher precedence than , has higher precedence than
8. Please translate the following program fragment into quadruple sequence. (10%)
i=1;
m=0;
loop=0;
n=0;
while (loop==0 && i<=10) {
j=1;
while (loop ==0 && j<=i)
Pb S d
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SS ; A|A AB|C Ba CD|D e A DE B Ei F t FF o G|G Gb
4. Please show that the following operator grammar is whether an operator precedence grammar by constructing the related parsing table. (10%) EE a F|F FF o T|T T(E)|n T|b
2) The initial value of variable X is 6, the start address of stack used in the program is K.
3) The stack map may get its maximum size for several times, here we ask you draw the stack map at maximum size for the third time.
B.val=0
B1
B.val=1
B2
B.val=2
B3
B.val=3
7. We assume that the storage organization and the form of activation
record used in C language program run-time stack storage allocation